I am currently planning a fantasy map, and I need some help with my research.
I know absolutely nothing about farming. Yet there are a number of farms featured in my novel that the map is based. I need to know how large a crop would need to be to support one person (thus I can scale it appropriately for the number of people then needed to be supported by the produce).
I am working on the assumption that the farmer would harvest two crops a year for the same patch of land (i.e. the winter crop and the summer crop). It wouldn't necessarily be the same produce.
How many square meters would the land need to be to generate a safe return of produce to support one person?

For ease of example, assume that the product in question is spelt/wheat.

Thanks in advance